Mixing devices are in wide use in industry, and many mixing devices include a large mixing vessel which contains a liquid to be mixed, and a typically vertical impeller shaft running down some or all of the vertical length inside the mixing vessel. The impeller shaft is typically rotatably driven by a motor output shaft, usually located at the top of the mixing vessel, and at one or several locations on the length of the impeller shaft radially extending impellers are mounted which have paddles or blade type features along some or all of the length and which mix and/or otherwise impart energy to the fluid inside the mixing vessel.
In some instances, a drive assembly along with some sealing arrangement are mounted at a top opening of the mixing vessel. Often times, the bottom end of the drive output shaft and the top end of the impeller shaft are each fitted with a coupling half, and the two coupling halves are bolted directly together in order to suspend the impeller shaft from the drive so that it extends vertically downward into the mixing vessel.
A disadvantage to this arrangement is that it is relatively permanent and once the drive output shaft's coupling half is bolted to the impeller shaft's coupling half, it is now difficult to then go back and disconnect the two without time consuming and disadvantageous unbolting processes. Therefore, these bolting systems are not very suitable for use in processes where it is often necessary to disconnect the motor output shaft from the impeller shaft in order to disconnect the drive from the rest of the mixing assembly. For example, sterile mixing assemblies are sometimes required in the biotech and pharmaceutical industry, and a known way to provide a sterile mixing assembly is place a mixing assembly into an autoclave where it is sterilized. However, the mixing assembly's drive is removed before the rest of the mixing assembly is placed into the autoclave. Because this known sterilization process involves removing the drive, the foregoing time consuming unbolting and bolting processes may be undesirable.
Accordingly, there is a need in the art for a coupling apparatus and method which can be fitted onto a drive output shaft and onto an impeller shaft, and which can be used to quickly connect and disconnect the shafts to and from each other.